Cell-Free DNA EGFR T790M Mutation Analysis, Blood
Use
This test is used for determining the EGFR T790M mutation status in blood specimens, which serves as an alternative to invasive tissue biopsies. It is particularly useful for identifying patients with non-small cell lung cancer who harbor a T790M mutation and may benefit from specific EGFR-targeted therapies such as osimertinib. It is particularly valuable in cases of metastatic NSCLC where this mutation leads to acquired resistance to EGFR-targeted tyrosine kinase inhibitors.
Special Instructions
This test detects only the T790M mutation in the EGFR gene and is not validated for serial monitoring of cancer patients or as a screening test to identify cancer. For tissue testing, the EGFR Gene, Targeted Mutation Analysis, 51 Mutation Panel should be ordered.
Limitations
The test is limited to detecting the EGFR T790M mutation using cfDNA from blood samples. The presence of cell-free DNA is a biological variable which can affect detection sensitivity, and false negatives are possible. This assay cannot differentiate between somatic and germline alterations and is not designed for therapy response monitoring or early tumor detection.
New York Approved
Methodology
PCR-based (ddPCR)
Biomarkers
LOINC Codes
- 55769-4
- 50397-9
- 55769-4
- 69047-9
- 48767-8
- 31208-2
- 18771-6
Result Turnaround Time
5-10 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
Two, 10-mL
Minimum Volume
One 10 mL Streck tube
Container
Streck Black/Tan Top Tube Kit (T715)
Collection Instructions
Only blood collected in Streck cfDNA tubes will be accepted for analysis. The whole blood will be processed to produce platelet-poor plasma before cfDNA isolation.
Storage Instructions
Samples should be transported at ambient temperature or refrigerated (4 degrees C).
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 7 days |